Heater casing for use with a dental press



Dec. 22, 1936. A. KElL HEATER CASING FOR USB WITH A DENTAL PRESS Filed March 21, 1955 1 //xz//z/z E w %u patente& Dec. 22, 1936 PATENT OFFICE HEATER CASING FOR US E WITH A DENTAL PRESS Alfred Keil, Berlin, Germany, assignor to Heko- Werk Chemische Fabrik A. G., Berlin-Tempelhof, Germany Application March 21, 1935, Serial No. 12,277 In Germany April 21, 1934 1 Claim.

The present invention relates to a press for producing artificial sets of teeth and particularly to a press of this kind adapted for the treatment of ormed dental plates made from some plastic prothese material. Presses for dental plates are known, at which the cuvette and the press spindle are arranged within a steam-heated autoclave. Presses of this kind are however not suited or the treatment of dental plates made from plastic materials which are sensitive to steam. When such material is used it has been proposed to employ spindle presses with heated upper and lower press plates. This arrangement however involves the drawback, that the cuvette located between the upper and the lower press plates is non-uniformly heated. This is particularly disadvantageous for the portions of the cuvette in which the lateral apertures are formed through which the excess of the plastic plate material is forced out during the pressing operation. Moreover, when the plastic mass to be pressed is of a very tough consistency the cold air entering the lateral apertures in the cuvette will hinder the excess material from fiowing out.

Experience has thereiore shown, that at presses of the said kind the heat must be applied to the press cover and the press bottom at a point lying particularly high above the flow level of the material. If for instance under unfavorable conditions the model must be arranged in inclined position within the cuvette it may occur that the parties of the gum on the inner side of the palate lie too near to the press bottom which is heated above the flow temperature of the material. This is very disadvantageous, because the porcelain teeth and the metal pins by means of which the teeth are held in the dental plates are particularly good conductors of heat, so that the parties of the plate material adjacent the over-heated press bottom (i. e. the palate parties) and the shafts of the teeth are discolored.

The chief object of the present invention is to avoid these drawbacks. According to the invention the upper and lower press plates are not heated separately, but the entire press is surrounded by a removable bell-shaped hood or casing, which preferably is made from a ceramic material (or from some other suitable material such as for instance glass, fiber or the like) and the interier of which is equipped with electric heating bodies. When the electric heating bcdies in this casing are switched in the press and the cuvette are uniformly heated from all sides and the pressing process takes place in an atmos- 55 phere the temperature of which is like the flow temperature of the material under treatment in the press. The drawbacks caused at the known presses, on account of the over-heating of the top and bottom members of the press and the admission of cold air, are thereiore avoided. 5

A preferred constructional form of the invention is shown by way of example in the accompanying drawing.

Fig. l is a front View, partially in section, showing a press for dental plates and the heating 10 casing according to the invention.

Fig. 2 is a Vertical sectional View showing the heating casing and two of the heating elements arranged therein.

Fig. 3 is a horizontal secticnal View, showing a 15 portion of the wall of the heating casing and a heating element arranged therein.

In the drawing l denotes the base or bottom plate of the press and 2 denotes posts which carry the upper transversal member 3 of the press. 20 This cross piece is formed with a threaded bore adapted to receive the threaded press spindle 4 which is rotated by means of a detachable handle 5. To the lower end of the press spindle the upper press plate 6 is attached which is guided by 25 the posts 2 and which by rotation of the press spindle 4 may be pressed against the top of the two-part cuvette 1. Before the elements of the model are placed in the cuvette the same are heated on a heating plate or the like in order to 3 remove the moisture from the same. When the said elements have been dried a plate of a plastic material is inserted between the elements which then are ready for the press treatment and are placed in the cuvette l.

8 is a heating casing of ceramic or some other suitable material. This casing is placed over the press so that it rests with its lower end on the insulating plate 9 which also carries the bottom plate l of the press. The top of the casing 8 is 40 formed with an aperture of sufficient width to allow the passage of the valve spindle 4. After the handle 5 has been removed, in order to prevent the introduction of air from the outside the space between the edge of the aperture o and the 45 spindle 4 may be closed by means of a removable annular member ll.

The heating casing 8 is equipped with electric heating elements l3, l4, which in the Constructional form shown in the drawing are arranged 50 diametrically opposite each other in the casing. The terminals !5, !6 of the heating elements may for instance be connected to a step switch, in order that the temperature may be controlled accurately.

It is of course not necessary to arrange the heating elements in the manner shown in the drawing. The same may for instance consist of one or more heating coils arranged on the inner Wall of the casing in the form of spirals ascending from the bottom of the casing to the top of the same. The heating bodies may also consist of circular elements arranged on the inner wall of the casing in horizontal planes one above another.

In order to protect the casing 8 of ceramic material against damage the same may be surrounded by a protective cap or jacket |1 of sheet metal or any other suitable material. This jacket is provided with insulated handles [8, s in order to facilitate the handling of the heating casing.

When the apparatus is put into use a charged cuvette is first placed in the press, whereupon the heating casing 8 is placed over the press and the heating current is switched in. As soon as the moisture from the model has escaped through the space between the edge of the hole n and the press spindle 4 this space is closed by means of the ring ll. 'I'hereupon the handle 5 is fixed to the spindle 4 and the press is actuated by rotating the handle. The interier of the casing is uniformly heated and the temperature in the apparatus can be accurately controlled and held at the height of the flow temperature of the mass under treatment. The temperature within the casing can be read off from the outside of the casing on a bent thermometer 2| which is fixed in a hole 20 in the casing. 22 denotes a window of transparent glass through which the interier of the casing may be inspected.

I claim:-

For use with a dental press having a spindle With a removable handle, a heat insulating bottom plate upon which the press rests, a heater casing of a material which is a bad conductor of heat, adapted to be placed over the press and seat upon said bottom plate but structurally independent of the press, said heater casing having a central aperture at the top for the press spindle but of greater diameter than said spindle, an annulus removably fitting into said aperture to fill the space between said spindle and the walls of the aperture, electrical heating elements on the inner wall of the casing and switching means on the outside of the casing by means of which the heating elements may be switched on or off as required.

ALFRED KEIL. 

